Add admin study user enrollment list

src/AdminPage.tsx

@@ -74,6 +74,12 @@ export interface AdminStats {
     enrolledUsers: number
     totalEnrollments: number
     enrollmentsByStudy: Array<{ slug: string; title: string; count: number }>
+    users: Array<{
+      id: string
+      username: string
+      displayName: string
+      enrolledStudies: Array<{ slug: string; title: string }>
+    }>
   }
 }
 
@@ -2332,6 +2338,32 @@ export default function AdminPage({ content, onSave, onLogout }: Props) {
                     }
                   </div>
                 </div>
+
+                <div className="admin-dashboard-activity" style={{ marginTop: '1rem' }}>
+                  <div className="admin-dashboard-activity-col" style={{ gridColumn: '1 / -1' }}>
+                    <h3 className="admin-dashboard-activity-heading">Study Users &amp; Enrollments</h3>
+                    {stats?.studyEnrollment?.users?.length
+                      ? (
+                        <div className="admin-dashboard-feed">
+                          {stats.studyEnrollment.users.map(user => (
+                            <div key={user.id} className="admin-dashboard-feed-item">
+                              <div className="admin-dashboard-feed-meta">
+                                <strong>{user.displayName || user.username}</strong>
+                                {user.displayName && <span className="admin-dashboard-feed-email">{user.username}</span>}
+                              </div>
+                              <div className="admin-dashboard-feed-preview">
+                                {user.enrolledStudies.length
+                                  ? `Enrolled in: ${user.enrolledStudies.map(study => study.title).join(', ')}`
+                                  : 'Not enrolled in any studies yet.'}
+                              </div>
+                            </div>
+                          ))}
+                        </div>
+                      )
+                      : <p className="admin-stats-note">No study users yet.</p>
+                    }
+                  </div>
+                </div>
               </section>
             )
           })()}